Audio and video playback systems of the type using an information-containing-disc having recorded information signals encoded into a fine spiral groove typically utilize a stylus to read the encoded information signals. Included in such systems are the capacitive playback systems, wherein the stylus dielectric material is coated on at least one surface with a conductive metal layer which interacts with the conductive disc to read the information encoded thereon. An example of such a system is disclosed in U.S. Pat. No. 3,842,194 issued Oct. 15, 1974 to Clemens. Clemens discloses a video disc having a playback system utilizing variable capacitance. In one configuration of the Clemens system, information representative of recorded picture and sound is encoded in the form of a relief pattern in a relatively fine spiral groove on the surface of the disc. For example, groove widths of about 2.5 micrometers and groove depths of about 1.0 micrometers may be used. During playback a pickup stylus having a shoe width of 2.0 micrometers and a thin conductive electrode formed thereon, for example about 0.2 micrometer thick, engages the groove as the record is rotated by a supportive turntable. Capacitive variations between the stylus electrode and the disc surface are sensed to recover the pre-recorded information. In systems of the above type, the use of a relatively fine record groove and the requirements for a groove engaging pickup stylus result in a stylus tip which is extremely small. Further, the length of the stylus shoe is critical because if it is too short the stylus may damage the disc due to excessive pressure. If the stylus shoe is too long, on the other hand, stylus life is reduced and electrical performance is degraded.
During the manufacturing of such styli it is often necessary to perform an operation, say a coning operation, on a stylus in one machine and then move the stylus to a different machine for performing another operation, say a faceting operation. Because of the extremely small dimensions involved, the stylus must be very accurately aligned when it is moved to the second machine. Heretofore, chucks having various structures have been utilized to hold these styli. The chucks are easily transfered from machine to machine and maintain accurate alignment when doing so, but only with respect to the first machining operation. Any machining operations performed on the stylus are necessarily only as accurate as the chuck. Therefore, any misalignment of the stylus holding jaws with respect to the shank of the chuck will be reflected in a similar misalignment of the machined surfaces of the stylus with respect to the axis of the stylus. What is needed is a stylus holding chuck having little or no misalignment of the stylus holding jaws with respect to the spindle of the machine which rotates the chuck.